What Is MRSA?

Methicillin-resistant Staphylococcus aureus (MRSA) are bacteria that can cause infections on the skin (such as cellulitis), on burned areas of the body, and around wounds where invasive devices like feeding tubes and catheters enter the body. MRSA can also infect the eyes, bones, heart, or blood. Unlike regular staph infections, MRSA is resistant to many commonly used antibiotics, including methicillin, used to kill bacteria. Decades ago, a strain closed a number of hospitals, recalls Robert A. Weinstein, MD, a spokesman for the Infection Diseases Society of America. Now a mutation of MRSA appears to be causing a new outbreak of infections outside of hospital settings – so-called community-acquired MRSA. The mystery is how and why. Partly, it's because “staph spreads readily," says Dr. Weinstein. "It seems to colonize better than other strains, and cause infections better. That’s why it’s called a superbug.”

What Causes MRSA?

People can still catch MRSA in hospitals or health-care settings, although Weinstein says rates of hospital-acquired MRSA have decreased in recent years. Medical devices, such as catheters and ventilation tubes, once accounted for 80 percent of MRSA skin infections; these numbers have dropped by 50 percent perhaps due to better infection control methods. What concerns doctors now is a close relative of hospital-associated MRSA that's on the rise in non-medical settings. Community-acquired MRSA is picked up “more [through] physical contact,” Weinstein explains. “If you culture 1,000 people, 20 percent to 30 percent will have [MRSA] in their nose.” These people are healthy carriers of the bug, but aren't sick themselves.

People at Risk for MRSA Infection

While healthcare-associated MRSA used to infect people with weakened immune systems, community-acquired MRSA is becoming more common in healthy individuals. According to Weinstein, high-risk individuals are people who are always around a lot of people — groups as wide-ranging as jail inmates and kids in daycare who share toys and saliva. Infectious disease specialists have also seen MRSA infect army recruits who share close quarters in their barracks. MRSA is found virtually everywhere there are shared facilities, including gym locker rooms. Another at-risk population, says Weinstein, are sexually active gay men.

Can Dogs and Cats Get MRSA?

MRSA can “ping-pong” between pets and owners, says Weinstein. If you can’t get rid of a MRSA skin infection, look at your pets, he cautions. MRSA has also been cultured from the nostrils of farm animals and farm workers; last year, researchers found it on a pig farm in the United States and in meat products in Europe. Thoroughly cooking meat should make eating this food safe, but experts are concerned that MRSA has now entered the food chain.

Symptoms of MRSA

Staph infections, including those caused by MRSA, most commonly affect the skin and soft tissues, Weinstein says. A MRSA skin infection could be minor (if it stays confined to a small area) or it could be very serious and spread through the bloodstream, threatening the rest of your body. Wounds associated with a less serious infection will be red, feel warm, and may exude pus; you may also have a fever. Community-acquired MRSA could also look like a spider bite or show up as deep or multiple abscesses. MRSA skin infections have also been confused with streptococcal or other infections of the skin like impetigo, folliculitis (inflamed hair follicles), infected cuts, cellulitis (a skin infection that also involves inflammation of connective tissues), or other skin problems.

With a more serious case of MRSA, you might experience headache, shortness of breath, chest pain, muscle aches, coughing, and fatigue. Get medical attention for any possible MRSA symptoms, even if they seem minor.

How Is MRSA Diagnosed?

A doctor who suspects MRSA will order medical tests to identify the type of bacteria causing the problem and the type of antibiotic needed to address it. There are various ways that doctors diagnose a MRSA infection, depending on the patient’s symptoms. Blood, fluid, or pus from the infected area, skin from the wound, sputum, or a urine specimen may be tested for the presence of the MRSA bacteria. Testing involves a process called culturing, which allows MRSA or any other bacteria in the specimen the opportunity to grow enough to be identified.

Facts About MRSA Treatment

If the MRSA infection has stayed in one spot, such as an abscess, then draining it is probably the only thing your doctor will need to do. But if the infection has become more widespread, or involves a larger area of skin, then antibiotics are necessary and treatment becomes more complicated. The reason: The list of drugs that can kill MRSA keeps getting shorter. Several antibiotics that may still work include clindamycin, daptomycin, doxycycline, linezolid (Zyvox), minocycline, tetracycline, trimethoprim-sulfamethoxazole (Bactrim, Bactrim DS, Septra, Septra DS), and vancomycin (Vancocin, Vancoled). Make sure you completely finish your prescribed antibiotics. If you don’t, you may allow a few remaining MRSA bacteria in your body to get more powerful and develop more resistance.

Cellulitis and MRSA Risk

Cellulitis develops when the deeper layers of your skin become infected from bacteria that has entered through a scratch or cut. Weinstein terms cellulitis an infection of the skin’s structure, and it’s painful. “Generally, it’s related to the apparent or unapparent breakdown of the skin, and then it implants [itself]. People think MRSA is good at setting up shop in there.” If properly taken care of, a skin infection normally stays within the top layers. Cellulitis goes deeper, however. On the surface you will experience a diffuse area of redness, warmth, and tenderness. If you have symptoms like this, call or see a doctor right away.

MRSA Complications

Weinstein says the biggest complications from MRSA are bloodstream infections (also referred to as sepsis or blood poisoning) and when MRSA reaches the heart. At that point, it can infect the heart valves, causing endocarditis, a condition in which the inside lining of the heart valves and heart chamber become inflamed. Other complications include pneumonia (as shown in the X-ray). Even young, healthy people have died when they contracted pneumonia or endocarditis from MRSA.

Preventing MRSA

There's no surefire way to prevent MRSA skin infections. If you are hospitalized, insist that all medical personnel wash their hands before examining you. At home and in your community, don't allow your kids to share their towels or personal athletic equipment. Keep all wounds clean and covered, and avoid contact with other people’s open wounds or their bandages. Careful antibiotic use may also be key. With antibiotics, says Weinstein, the more they are used in the general population, the quicker they lose their effectiveness against the bugs they're supposed to kill. In the Netherlands, for instance, people aren’t experiencing the antibiotic-resistance issues Americans have because the Dutch use a fraction of the antibiotics used in the United States, says Weinstein. The bottom line: Don't use antibiotics unnecessarily, such as for colds and other viral infections.

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